An LP-based tabu search for batch scheduling in a cutting process with finite buffers

This paper addresses a cutting stock problem under typical resource constraints that arise when working centres with nesting capabilities are associated with automatic feeders/stackers. The critical resource is the number of buffers available to host the batches built up by the centre. To cope with it, pattern and batch sequencing problems must be addressed simultaneously. A tabu-search algorithm exploring batch output sequences is proposed. The algorithm never opens more stacks than buffers, respects batch compatibility/precedence constraints, and keeps the maximum order spread under control. To demonstrate its effectiveness and efficiency, a computational study was set up, solving 920 test problems derived from the literature. The study enabled a proper tuning of the method and offered encouraging results: in 228 cases an optimum was found; in nearly all, the gap from the optimum was below 1%. Computation times range from fractions of seconds to a couple of minutes in the worst cases. Compared to existing methods, the algorithm provides on average the same solution quality, with the advantage of solving a problem which is more general and hence closer to application. The paper includes a discussion on the method extensions required to deal with asynchronous stacking and heterogeneous batches.     

The classical roots of the Austrian theory of capital and entrepreneurship

The paper deals with the continuities and discontinuities between some classical, Austrian and neo-Austrian authors with regard first to the theory of capital and then to the theory of entrepreneurship. Part I focuses on the elements of continuity between the classical and the Austrian theory of capital. These elements have been singled out by dealing first with the distinction between individual and national capital; and then with the difference between the resulting circulating-fixed capital and free-invested capital distinctions in the light, first, of the concept of roundaboutness and, then, of the method of vertical integration. Part II focuses on the elements of continuity between the Austrian theory of individual behaviour and the classical theory of national wealth. The distinctions between logical and historical time and between economics of time and economics in time are used to assess the links between the theory of capital as developed by the classics and Böhm-Bawerk, on the one hand, and the theory of entrepreneurship as developed by the neo-Austrians, on the other.     

The Role of Comprehensive Income as Financial Performance Predictor： Panel Evidence From Italy

The aim of this study is to investigate whether the comprehensive income （CI） and its individual components are useful in assessing the future cash flows for Italian listed companies. In addition, we verify whether the recent requirement of International Accounting Standard （IAS） 1 （r2011） of providing the other comprehensive income （OCI） separates in two sub-totals （recycling and non-recycling items groups） is useful to explain the expected cash flows. We consider a sample of 121 Italian non-financial companies listed on the Italian Stock Exchange for the testing period of 2008-2011, employing a fixed-effect regression model, and we test the relationship between the changes in the variables considered and not the relative absolute value reducing, in this way, the risk of not grasping a report if the independent variable and the response variable do not have the same sign. Our results stress that CI and the two new sub-aggregates are not relevant to explain future cash flows, while net income （NI） and OC1 as a whole seem to be more relevant to make explicit the future financial position. The study contributes, as a sort of post-implementation review, to the current debate on the ability of Cl to predict the future cash flows and on the real usefulness of the CI and the sub-aggregate identified by the IAS 1 revised as well.     

UNCERTAINTY AND EXPECTATIONS IN SHACKLE'S THEORY OF CAPITAL AND INTEREST

This paper is focused on the macroeconomic aspects of Shackle's theory of capital and interest. The paper highlights the strengths and weaknesses of this theory. Among the strengths is Shackle's treatment of historical time, expectations and their disappointment, ex ante and ex post magnitudes, macroeconomic equilibrium and disequilibrium. Among the weaknesses is Shackle's failure to grasp the difference between the theory of interest as such and the theory of the money rate of interest as well as the difference between the theory of capital in the context of logical time (the old Austrian approach) and the theory of capital in the context of historical time (Hayek's and Shackle's preferred approach).

相似文献   

Different divisions of capital in Smith,Ricardo, and Marx

An earlier version of this paper was presented at the Twenty-Sixth Atlantic Economic Society Conference, October 6–9, 1988, Philadelphia, Pennsylvania. The author wishes to thank Hans E. Jensen for helpful suggestions. The usual disclaimer applies.     

From bounties on exportation to the natural and market price of labour: Smith versus Ricardo

Abstract

The scope of this article is to examine the foundations of Smith's arguments and of Ricardo's criticisms on the issue of bounties on exportation. These criticisms are examined in the light of the counter-criticisms provided by a fictitious subject called Smith redivivus. These counter-criticisms highlight Ricardo's neglect of the differences between vérité de raison and vérité de fait and between the points of view of an individual and of society behind Smith's treatment of money vs. real, temporary vs. permanent and natural vs. market price of labour as labour and of commodities as products of labour.     

Skill bias, trade, and wage dispersion

Wage ratios between different percentiles of the wage distribution have moved in parallel and then diverged in the U.S. in the last 50 years. In this paper, I study the theoretical response of wage ratios to skill-biased technical change and trade integration. I build a simple model of heterogeneous technology and heterogeneous workers that features complementarities between the quality of ideas and abilities. I show that changes to the skill bias of technology and to trade costs can both reproduce the observed pattern since (i) they have similar asymmetric effects on productive vs. unproductive firms, and (ii) positive assortative matching in the labor market transmits this asymmetry across high and low skill workers. Focusing on the different channels through which skill-biased technical change and trade integration operate suggests ways to disentangle the magnitude of each.